E.T.
I have three girl 11, 5 and 2. The 5yr old and 2yr old share a room. However they all help in cleaning their room. I let them go in and clean to a point they think it is "good" and then I go in after them and put all the stuff that is not in the correct place in the middle of the room. I then let them do a second round. They do come to me while putting stuff away from the middle of the room asking where it should go - and at that point I help them decide the best place for it or where it exactly belongs. This system seams to work for us and each time there is less stuff I end up putting in the middle of the room.